Problem: $-6pq + 5pr - p - 10 = 6q - 9$ Solve for $p$.
Answer: Combine constant terms on the right. $-6pq + 5pr - p - {10} = 6q - {9}$ $-6pq + 5pr - p = 6q + {1}$ Notice that all the terms on the left-hand side of the equation have $p$ in them. $-6{p}q + 5{p}r - 1{p} = 6q + 1$ Factor out the $p$ ${p} \cdot \left( -6q + 5r - 1 \right) = 6q + 1$ Isolate the $p$ $p \cdot \left( -{6q + 5r - 1} \right) = 6q + 1$ $p = \dfrac{ 6q + 1 }{ -{6q + 5r - 1} }$